Posted by Øystein rustad (213.145.185.102) on February 03, 2003 at 03:14:50:
In Reply to: Theoretical output power from a wheel? posted by Vector Viper on February 03, 2003 at 03:07:01:
Know facts from Besslers latest and biggest wheel are :
(The previous wheel had a better weight to power ratio,
I think ?)
Diameter : 3,65 m
Weights : 9 Kg (Estimated by Collins)
RPM : 20
Load : 34Kg pulled around the axle
Axle diameter : 15,24 cm
Power exctracted from the machine at 20 RPM will then be :
F*Dpr.sek =
34kg*9,8m/s^2*3,14*0,1524*20/60 = 53,2Watts
What we don`t know is how many weights he used.
It is known that the weights worked in pairs (of two?)
And that about 8 bumps where heard pr. revolution.
1. It could be that he used 8 , 9 Kg weight, and 8 weights working in pairs with the first 8 (somewhere from 3 to 9 Kg) (totally 16 weights)
2. He could also have used 4 , 9Kg weights and 4 weights somewhere from 3 to 9Kg.
This is my basic theory !
Anyway I got a formula for calculating the Power from his latest design that looks like this :
P = pi*m*d^1/2
(Where d = diameter and m = the weight of one of the (biggest) weights and pi = 3,14 :-)
In this case the formula adds up to 54 Watts (theoretically)!!
Øystein
: I have done some calculations tonight and it seems
: my best wheel design (on paper) might be able to put out
: 200 watts of work using only 2 10 pound weights.
: It is a theoretical 6 foot wheel running at 125 rpm...
: Am I in the ball park here-or did I goof?
: How does this compare with others?
: Jeez...
: It's barely enough to run a tv set!! assuming 100% conversion
: to electricity of course...
: Viper